Roller rock bit



Dec. 8, 1936. A. c. CATLAND I 2,063,012,

' ROLLER ROCK BIT Filed Oct. 14, 1935' Pg! Fg'qZ AL FEED C. (Ana/v0 l/vvnv ran j Arramzv Patented Dec. 8, 1936 UNITED STATES PATENT OFFICE ROLLER ROCK BIT Application October 14, 1935, Serial No. 44,852

11 Claims.

This invention relates to a well drilling tool and relates more particularly to a rock bit for use in the rotary method of well drilling. A general object of this invention is to provide a roller rock bit that is rapid and efi'lcient in operation and that is simple and sturdy in construction.

Another object of this invention is to provide a well bit that embodies a simple one piece bearing member or spider rotatably supporting the several roller cutters, which spider is removably 'attached to the shank in a simple dependable manner.

Another object of the invention is to provide a roller well bit embodying a choke nipple for discharging the circulation fluid that is removably secured to the shank in a manner so that it forms a means for assisting in securing the cutter carrying spider to the shank.

Another object of this invention is to provide a rock bit embodying inner roller cutters and outer roller cutters mounted and related'to be particularly rapid and efiicient in their cutting action.

A further object of this invention is to provide a roller rock bit that may be very easily and quickly repaired and reconditioned when the cutters, etc. become worn. a

The various objects and features of my invention will be fully understood from the following detailed description of a typical prefered form and application of my invention, throughout which description reference is made to the accompanying drawing, in which:

Fig. 1 is a side elevation of the bit provided by the present invention with a portion broken away to appear in vertical cross section.v Fig. 2 is a vertical detailed sectional view of the bit taken in a plane at right angles to the plane of sectioning of Fig. 1. Fig. 3 is a bottom elevation of the shank with the cutter mounting member removed. Fig. 4 is a bottom elevation of the bit and Fig. 5 is a bottom elevation of the cutter carrying member or spider with the cutters removed.

The Well drilling bit provided by the present invention includes, generally, a body or shank ill, a removable bearing member or spider II on the shank l0, inner cutters l2 rotatably supported by the spider I l and outer cutters l3 rotatably supported by the spider I I.

The body or shank IU of the bit is adapted to be connected with the lower end of a drilling string. The shank I0 is a simple integral member having means at its upper end for connecting with the drilling string and having its lower end shaped and formed to carry the spider ll, etc. In the typical form of the invention illustrated in the drawing the shank I0 is cylindrical in its general configuration and is provided at its upper end with a tapered screw threaded pin M for facilitating its connection with a drilling string. The lower face l5 of the shank III is flat and is preferably substantially horizontal. In accordance with the invention the shank I0 is provided with downwardly extending projections or legs. There are two substantially diametrically opposite legs l6 projecting iTrom the lower end face I5 adjacent the periphery of the shank. The legs l6 may project outwardly as well as downwardly from the shank I0 and their inner sides H are inclined downwardly and outwardly. The shank i0 is provided with a third leg l8 projecting downwardly from its lower end adjacent its periphery. The inner side or surface 19 of the leg [8 is inclined downwardly and inwardly relative to the central vertical axis 01' the bit. The leg [8 is integral with the shank III and is spaced approximately 90 from the legs IS.

The bearing member or spider II for carrying the cutters l2 and I3 is preferably a simple onepiece member as illustrated throughout the drawing. The spider ll includes an inner part or hub 20 having a fiat upper surface 2| for seating or bearing against the lower face l5 of the shank. The hub 20 is preferably comparatively thick 'vertically and is provided with a vertical opening 22. The spider ll includes projecting parts or arms for carrying the cutters l2 and I3. Two arms 23 project from the lower portion of the spider hub 20 and lie in a plane substantially diainetric of the central vertical axis of the shank ID. The major portions of the arms 23 are cylindrical to rotatably carry the cutters l3 and their longitudinal axes are inclined downwardly and inwardly with respect to the longitudinal axis of the shank. Recesses 24 are provided in the inner sides I! of the legs IS. The

recesses 24 extend upwardly from adjacent the lower ends of the legs l6 and have fiat parallel side walls and curved or concaved upper walls.

The arms 23 of the spider II have reduced outer end portions 25 which enter the recesses 24 and bear upwardly against their upper walls.

The extreme outer ends of the arms 23 are adapted to bear against the bottom walls of the recesses 24. The reduced portions 25 of the arms 23 provide the arms with annular outwardly facing shoulders 26- which are spaced from the inner aides ll of the legs l6.

The spider II has a third arm 21 for carrying the inner cutters I2. The arm 21 pro jects downwardly and outwardly from. the lower portion of the hub 23 and is cylindrical to rotatably carry the inner cutters I2. In the preferred construction the arm 21 is inclined downwardly and outwardly relative to the central vertical axis of the shank III. The cutter carrying arm 21 is spaced approximately 93 from the arms 23 and its outer end is adapted A groove or to cooperate with the shank leg I3. recess-23 is providedin the inner surface I3 of .the leg I3 to receive a reduced endportion 23 of the arm 21. The recess 23 may be similar in shape to the recesses 24. The extreme outer end of the arm 21 is adapted to bear against the bottom orouter wall of the recess 23 and the reduced portion 23 is adaptedv to bear upwardly against the upper wall of the recess. The reduced end portion 23 provides the arm 21 with an outwardly facing annular shoulder 33 which is spaced from the leg I3.

The invention provides novel eflfective means for tying the arms 23 to the legs I6 and the arm 21 to the leg I3 and for assisting in removably securing the spider to the shank I 3. Central longitudinal openings 3| extend through the arms 23 from one end to the other and a similar opening 32 extends through the arm 21. Screws 33 are passed into the openings 3| from their inner ends and are threaded into openings 34 in the legs I6. The heads 35 of the screws 33 are received in counter bores in the inner ends of the openings 3|. Cotter keys 36 extend into the counter bores of the openings 3| to prevent unthreading of the screws 33. A screw 31 is passed into the opening 32 from its inner end and is threaded into an opening 33 in the leg I 3. The head 33 of the screw 31 is received in a counter bore in the inner end of the opening 32. The screw 31 is retained against loosening and displacement in the manner to be hereinafter described. The screws 33 efiectively tie the arms 23 to the legs I5 while the screw 31 eifectively ties the arm 21 to the leg I3. The positioning or arrangement of the screws 33 and 31 is important. The screws 33 and 31 being arranged with their heads 35 and 33 in counter bores in the spider II do not necessitate the formation of counter bores in the legs I6 or I3 and, therefore, do not necessitate the weakening of the legs. A second advantage resulting from the above described arrangement of the screws 33 and 31 is that the heads 35 and 33 of the screws and the counter bores receiving the heads are not worn away or destroyed to make the removal of the screws dimcult in the event that the bit is worn excessively under gauge.

The inner cutters I2 are provided to act on the central or inner portion of the bottom wall of the well bore. The inner cutters I2 are rotatably supported on the spider arm 21 to project downwardly beyond the lower end of the spider and the leg I 3. In the particular form of the invention illustrated in the drawing there are two inner cutters mounted on the arm 21 in side by side relation. The innermost cutter I2 is frusto-conical having axially extending cutting teeth 43 inclined with respect to its axis of rotation. The outer cutter I2 may be cylindrical in its general configuration having axially extending teeth 4I equidistant from its axis of rotation. The openings of the cutters I2 have counter bores 42 which carry anti-friction bearings 43 for supporting the cutters on the arm 21. A recess 44 is provided in the outer end of the innermost cutter I2 to receivea spacer orthrust washer 45. A recess 46 is provided in the outer end of the outer cutter I2 to receive a thrust washer 41. The thrust washer 41 bears between the inner surface I3 of the leg I3 and the annular shoulder 33 of the arm 21. The thrust washer 41 has shouldered engagement with the leg I3 at 43 which holds it against rotation on the arm 21. During rotation of the bit the frusto-conical cutter I2 operates to leave a central substantially conical projection on the bottom of the well bore and the cooperation of the cutter with this raised portion of formation assists in centering and stabilizing the bit.

The outer cutters I3 are provided to cut or drill the outer portion of the well bore and ream the bore to size. An outer roller cutter I3 is rotatably supported on each arm 23 of'the spider II. The outer cutters I3 are frusto conical and are arranged with their small ends innermost. Counter bores 53 are provided in the openings of the cutters I3 to carry anti-friction roller bearings 5| which support the cutters on the arms 23. Recesses 52 are provided in the outer ends of the cutters I3 to receive thrust washers. 53. The thrust washers 53 are arranged on the arms 23 to bear between the shoulders 23 and the inner sides I1 of the legs I6. The thrust washers 53 have shouldered engagement with the legs I6 at 54, which engagement holds the washers against turning.

The outer cutters I3 have axially extending teeth 55 on their peripheries which project downwardly and outwardly from beyond the lower ends of. the legs I6 to act on the earth formation. The outer corners of the teeth 55 are bevelled away at 56 to properly cut or ream the side wall of the well bore. The frusto-conical outer cutters I3 mounted to rotate about downwardly and inwardly inclined axes have their cutting parts substantially horizontal as they come into engagement with the formation at the bottom wall of the bore and have their bevelled ends 56 substantally vertical as they act on the formation. In practice the inner and outer cutters I2 and I3 are mounted and proportioned to overlap in their action on the formation at the bottom of the well bore.

The invention includes means for handling the circulation fluid to fully flush the cutters and to materially assist in the drilling action. A vertical socket 43 is provided in the pin I4 of the shank I3 and is adapted to communicate with the lower end of the fluid passage in the drilling string. Ports 51 are provided in the shank I3 to extend downwardly from the socket 43 and discharge from the lower face I5 at points where the circulation fluid effectively flushes the cutters I2 and I3. A vertical port 53 of comparatively large diameter extends downwardly from the lower end of the socket 43 to the face I5. A replaceable wear taking flow nipple 53 is threaded in the lower portion of the port 53 and projectsv downwardly from the face I5. The nipple 53 projects into the spider opening 22 with substantial clearance. A nozzle member or choke 63 is arranged in the opening 22 to surround the nipple .53. The nipple 53 arranged with a portion in the port I5 and a portion in the choke 63 projects the shank I3 and the choke 33 against the abrasive action of the solid matter in the circulation fluid. The choke 63 projects downwardly so that its lower end is comparatively close to the bottom of the well bore. The choke the nipple 60 upwardly against the spider II and 60 is provided with a fluid discharge opening 6| in the form of a slot elongated radially with respect to the central vertical axis of the bit. The fluid discharging from the opening 6| adjacent the bottom wall of the well bore is particularly effective in eroding or disintegrating the formation. As the opening 6| is elongated radially in horizontal cross section the fluid is discharged in a manner to have a sweeping action as it moves across the bottom of the well bore.

The invention provides effective means for removably securing the choke 60 to the shank l0. Ears or flanges 62 are provided on the choke 60 and are adapted to bear upwardly against the lower face 2| of the spider hub 20. Screws 63 are passed upwardly through openings 64 in the flanges 62 and openings 65 in the spider hub 20 to thread into openings 66 in the lower end of the shank Ill. The heads of the screws 63 are preferably countersunk in the lower ends of the openings 64. Cotter keys 6! project into the counter bores of the openings 64 to prevent unthreading of the screws 53. The screws 63 clamp the flanges of tightly clamp the upper surface 2| of the spider against the lower face I5 of the shank Ill. The choke 60 thus acts as a securing member or medium for attaching the spider II to the shank Ill. The choke 60' is proportioned to project in front of and partially cover the inner end of the opening 32 so that it prevents loss or displacement of the screw 31. Accordingly, the choke 60 also acts as a lock member to prevent loss of the screw 31.

In operation of the bit the shank I0 is attached to the lower end of a drilling string and the bit is rotated and fed downwardly in the well in the usual manner. The inner cutters l2 act on andcut away the formation at the inner or central portion of the well. The circulation fluid under pressure discharging from the choke opening 6| impinges downwardly against the formation adjacent the center of the bore. The fluidmay erode the formation and thus assist the cutters H in their cutting action. The fluid discharged from the ports 51 fully flushes the cutters I2 and I3. The conical cutter l2 rotatably supported on the inclined arm 21 leaves a centrally disposed substantially conical piece of projecting earth formation and its engagement with this centering pro jection stabilizes the bit. The outer roller'cutters l3 act on the outer portion of the well bore and cut the bore to size. The cutters l2 and I3 are mounted for free rotating and are dependably fitted on their mountings. The screws 33 and 31 tie together the legs of the shank l0 and the arms of the spider II to materially strengthen the bit construction. The choke 60 operates to hold the spider upwardly against the lower face 15 of the shank l0 and serves to prevent displacement of the screw 31. spider I I may be easily and quickly removed from the shank III to permit the replacement of the cutters, etc. The flow nipple 59 may be replaced when worn. The choke 60 connected with the shank l0 by the screws 63 dependably secures the spider to the shank and is readily removable for replacement, etc.

Having described only atypical preferred form and application of my invention, I do not wish to be limited or restricted to the specific details herein set forth,-but wish to reserve to myself any variations or modifications that may appear to those skilled in the art or fall within the scope of the following claims.

Having described my invention, I claim:

When the cutters become worn the 1. A well bit including a shank, a spider bearing against the lower end of the shank, there being a fluid passage in the shank, a fluid discharge member communicating with the passage and engaging against the spider, and a plurality of independent means securing the member to the shank at points spaced from the passage and urging the member against the spider to clamp the spider to the shank.

2. A well bit including a shank, a spider bearing against the lower end of the shank, there being a fluid passage in the shank, a fluid discharge member communicating with the passage and engaging against the spider, and screws spaced from the passage and attaching the member to the shank and forcing the member upwardly against the spider to secure the spider to the shank.

3. A well drillingbit including a shank having a fluid passage, cutters, a spider carrying the cutters and bearing upwardly against the lower end of the shank, the spider having a fluid discharge opening, a fluid discharge member extending into the opening to receive fluid from the passage and engaging upwardly against the spider, a tubular wear taking nipple threaded in the passage and extending into the said fluid discharge member; and means attaching the member to the shank and holding the spider upwardly against the shank.

4. A well bit-including a shank having projecting legs, a member at the lower end of the shank, the member comprising arms projecting outwardly toward the legs, cutters rotatably supported by the arms, there being openings in the arms, and screws entered in the openings from their inner ends and threaded in openings in the legs to tie together the arms and legs.

5. A well bit including a shank having a downwardly projecting leg, a member at thelower end of the shank provided with an arm projecting outwardly to the leg, there being a longitudinal opening in the arm, a cutter rotatably supported bythe arm, and a screw introduced in said opening from its inner end and threaded into an opening in the leg to connect the arm and leg.

6. A well bit including a shank, a spider bearing against the lower end of the shank, there being a fluid passage in the shank, a fluid discharge member communicating with the passage and engaging against the spider, a wear taking nipple having an end portion in the passage and its opposite end portion in the discharge member, and means securing the member to the shank and urging the member against the spider to clamp the spider to the shank.

7. A well bit including a shank having a fluid passage, a leg projecting from the lower end of the shank, a spider at the lower end of the shank having an arm projecting outwardly to the leg, a cutter rotatably supported by the arm, a fluid discharge member communicating with the passage and engaging upwardly against the spider, means securing the member to the shank and forcing the member upwardly against the spider to clamp the spider to the shank, there being an opening in the arm, and a screw entered in the opening from its inner end and threaded into the leg to tie the arm to the leg.

8. A well bit including a shank having a fluid passage, a leg projecting from the lower end of the shank, a spider at the lower end of the shank having an arm projecting outwardly to the leg, a cutter rotatably supported by the arm, a fluid discharge member communicating with the passage and engaging upwardly against the spider, means securing the member to the shank and forcing the member upwardly against the spider to clamp the spider to the shank, there being an opening in the arm having its inner end adjacent the discharge member, and a screw entered in said opening from its inner end and threaded into the leg to tie the arm to the leg, the discharge member extending across the inner end of the opening to prevent unthreading of-the screw.

9. A well bit includinga shank having a fluid passage, aleg projecting from the lower end of the shank, a spider at the lower end of the shank having an arm projecting outwardly to the leg, a cutter rotatably supported by the arm, a fluid discharge member communicating with the passage and engaging upwardly against the spider, means securing the member to the shank and forcing the member upwardly against the spider to clamp the spider to the shank, said means including' a screw engaging the discharge member and threaded into the shank, there being a longitudinai opening in the arm, and a screw entered in the inner end of the opening and threaded in the leg to tie the arm and leg together, the discharge member being positioned at the inner end of the opening to prevent unthreading of the last named screw.

10. A well bit including, a shank, roller cutters rotatably carried by the shank to act on the formation at circumferentially spaced points to maintain the well bore to gauge, a member removably attached to the shank, and an inner roller cutter carried by the member to act on the formation within the path of the outer cutters. there being a fluid passage in the shank, the member having a fluid carrying port communicating with and receiving fluid from the passage, the walls of the port acting to conflne the fluid and being formed to provide a discharge end of elongate cross section discharging the fluid downwardly adjacent the bottom of the bore.

11. A well bit including, a shank, roller cutters rotatably carried by the shank to act on the formation at circumferentially spaced points to maintain the well bore to gauge, a member removably attached to the shank. and an inner roller cutter carried by the member to act on the formation within the path of the outer cutters, there being a fluid passage in the shank, the member having a main port receiving fluid from the passage and discharging it downwardly against the formation at the bottom of the bore and having reduced ports discharging streams of fluid against the several cutters.

ALFRED C. CA'I'LAND. 

